How effective and cost-effective is water fluoridation for adults? Protocol for a 10-year retrospective cohort study

Effect of fluoridated water on invasive NHS dental treatments for adults: the LOTUS retrospective cohort study and economic evaluation

Background

Most water fluoridation studies were conducted on children before the widespread introduction of fluoride toothpastes. There is a lack of evidence that can be applied to contemporary populations, particularly adolescents and adults.

Objective

To pragmatically assess the clinical and cost effectiveness of water fluoridation for preventing dental treatment and improving oral health in a contemporary population of adults, using a natural experiment design.

Design

Retrospective cohort study using routinely collected National Health Service dental claims (FP17) data.

Setting

National Health Service primary dental care: general dental practices, prisons, community dental services, domiciliary settings, urgent/out-of-hours and specialised referral-only services.

Participants

Dental patients aged 12 years and over living in England (n = 6,370,280).

Intervention and comparison

Individuals exposed to drinking water with a fluoride concentration ≥ 0.7 mg F/l between 2010 and 2020 were matched to non-exposed individuals on key characteristics using propensity scores.

Outcome measures

Primary: number of National Health Service invasive dental treatments (restorations/'fillings' and extractions) received per person between 2010 and 2020. Secondary: decayed, missing and filled teeth, missing teeth, inequalities, cost effectiveness and return on investment.

Data sources

National Health Service Business Services Authority dental claims data. Water quality monitoring data.

Primary outcome

Predicted mean number of invasive dental treatments was 3% lower in the optimally fluoridated group than in the sub/non-optimally fluoridated group (incidence rate ratio 0.969, 95% CI 0.967 to 0.971), a difference of -0.173 invasive dental treatments (95% CI -0.185 to -0.161). This magnitude of effect is smaller than what most stakeholders we engaged with (n = 50/54) considered meaningful.

Secondary outcomes

Mean decayed, missing and filled teeth were 2% lower in the optimally fluoridated group, with a difference of -0.212 decayed, missing and filled teeth (95% CI -0.229 to -0.194). There was no statistically significant difference in the mean number of missing teeth per person (0.006, 95% CI -0.008 to 0.021). There was no compelling evidence that water fluoridation reduced social inequalities in treatments received or missing teeth; however, decayed, missing and filled teeth data did not demonstrate a typical inequalities gradient. Optimal water fluoridation in England in 2010-20 was estimated to cost £10.30 per person (excluding original setup costs). Mean National Health Service treatment costs for fluoridated patients 2010-20 were 5.5% lower per person, by £22.26 (95% CI -£23.09 to -£21.43), and patients paid £7.64 less in National Health Service dental charges per person (2020 prices).

Limitations

Pragmatic, observational study with potential for non-differential errors of misclassification in fluoridation assignment and outcome measurement and residual and/or unmeasured confounding. Decayed, missing and filled teeth data have not been validated. Water fluoridation cost estimates are based on existing programmes between 2010 and 2020, and therefore do not include the potentially significant capital investment required for new programmes.

Conclusions

Receipt of optimal water fluoridation between 2010 and 2020 resulted in very small health effects, which may not be meaningful for individuals, and we could find no evidence of a reduction in social inequalities. Existing water fluoridation programmes in England produced a positive return on investment between 2010 and 2020 due to slightly lower National Health Service treatment costs. These relatively small savings should be evaluated against the projected costs and lifespan of any proposed capital investment in water fluoridation, including new programmes.

Future work

National Health Service dental data are a valuable resource for research. Further validation and measures to improve quality and completeness are warranted.

Trial registrations

This trial is registered as ISRCTN96479279, CAG: 20/CAG/0072, IRAS: 20/NE/0144.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Public Health Research programme (NIHR award ref: NIHR128533) and is published in full in Public Health Research; Vol. 12, No. 5. See the NIHR Funding and Awards website for further award information.

Economic evaluation of a water fluoridation scheme in Cumbria, UK

OBJECTIVES

The addition of fluoride to community drinking water supplies has been a long-standing public health intervention to improve dental health. However, the evidence of cost-effectiveness in the UK currently lacks a contemporary focus, being limited to a period with higher incidence of caries. A water fluoridation scheme in West Cumbria, United Kingdom, provided a unique opportunity to study the contemporary impact of water fluoridation. This study evaluates the cost-effectiveness of water fluoridation over a 5-6 years follow-up period in two distinct cohorts: children exposed to water fluoridation in utero and those exposed from the age of 5.

METHODS

Cost-effectiveness was summarized employing incremental cost-effectiveness ratios (ICER, cost per quality adjusted life year (QALY) gained). Costs included those from the National Health Service (NHS) and local authority perspective, encompassing capital and running costs of water fluoridation, as well as NHS dental activity. The measure of health benefit was the QALY, with utility determined using the Child Health Utility 9-Dimension questionnaire. To account for uncertainty, estimates of net cost and outcomes were bootstrapped (10 000 bootstraps) to generate cost-effectiveness acceptability curves and sensitivity analysis performed with alternative specifications.

RESULTS

There were 306 participants in the birth cohort (189 and 117 in the non-fluoridated and fluoridated groups, respectively) and 271 in the older school cohort (159 and 112, respectively). In both cohorts, there was evidence of small gains in QALYs for the fluoridated group compared to the non-fluoridated group and reductions in NHS dental service cost that exceeded the cost of fluoridation. For both cohorts and across all sensitivity analyses, there were high probabilities (>62%) of water fluoridation being cost-effective with a willingness to pay threshold of £20 000 per QALY.

CONCLUSIONS

This analysis provides current economic evidence that water fluoridation is likely to be cost-effective. The findings contribute valuable contemporary evidence in support of the economic viability of water fluoridation scheme.

The fluorosis conundrum: bridging the gap between science and public health

Fluorosis, a chronic condition brought on by excessive fluoride ingestion which, has drawn much scientific attention and public health concern. It is a complex and multifaceted issue that affects millions of people worldwide. Despite decades of scientific research elucidating the causes, mechanisms, and prevention strategies for fluorosis, there remains a significant gap between scientific understanding and public health implementation. While the scientific community has made significant strides in understanding the etiology and prevention of fluorosis, effectively translating this knowledge into public health policies and practices remains challenging. This review explores the gap between scientific research on fluorosis and its practical implementation in public health initiatives. It suggests developing evidence-based guidelines for fluoride exposure and recommends comprehensive educational campaigns targeting the public and healthcare providers. Furthermore, it emphasizes the need for further research to fill the existing knowledge gaps and promote evidence-based decision-making. By fostering collaboration, communication, and evidence-based practices, policymakers, healthcare professionals, and the public can work together to implement preventive measures and mitigate the burden of fluorosis on affected communities. This review highlighted several vital strategies to bridge the gap between science and public health in the context of fluorosis. It emphasizes the importance of translating scientific evidence into actionable guidelines, raising public awareness about fluoride consumption, and promoting preventive measures at individual and community levels.

How effective and cost-effective is water fluoridation for adults and adolescents? The LOTUS 10-year retrospective cohort study

OBJECTIVE

To pragmatically assess the clinical and cost-effectiveness of water fluoridation for preventing dental treatment and improving oral health in a contemporary population of adults and adolescents, using a natural experiment design.

METHODS

A 10-year retrospective cohort study (2010-2020) using routinely collected NHS dental treatment claims data. Participants were patients aged 12 years and over, attending NHS primary dental care services in England (17.8 million patients). Using recorded residential locations, individuals exposed to drinking water with an optimal fluoride concentration (≥0.7 mg F/L) were matched to non-exposed individuals using propensity scores. Number of NHS invasive dental treatments, DMFT and missing teeth were compared between groups using negative binomial regression. Total NHS dental treatment costs and cost per invasive dental treatment avoided were calculated.

RESULTS

Matching resulted in an analytical sample of 6.4 million patients. Predicted mean number of invasive NHS dental treatments (restorations 'fillings'/extractions) was 3% lower in the optimally fluoridated group (5.4) than the non-optimally fluoridated group (5.6) (IRR 0.969, 95% CI 0.967, 0.971). Predicted mean DMFT was 2% lower in the optimally fluoridated group (IRR 0.984, 95% CI 0.983, 0.985). There was no difference in the predicted mean number of missing teeth per person (IRR 1.001, 95% CI 0.999, 1.003) and no compelling evidence that water fluoridation reduced social inequalities in dental health. Optimal water fluoridation in England 2010-2020 was estimated to cost £10.30 per person (excludes initial set-up costs). NHS dental treatment costs for optimally fluoridated patients 2010-2020 were 5.5% lower, by £22.26 per person (95% CI -£21.43, -£23.09).

CONCLUSIONS

Receipt of optimal water fluoridation 2010-2020 resulted in very small positive health effects which may not be meaningful for individuals. Existing fluoridation programmes in England produced a positive return on investment between 2010 and 2020 due to slightly lower NHS dental care utilization. This return should be evaluated against the projected costs and lifespan of any proposed capital investment in water fluoridation, including new programmes.

Rice husk biochar - A novel engineered bio-based material for transforming groundwater-mediated fluoride cycling in natural environments

Biochar, a promising carbon-rich and carbon-negative material, can control water pollution, harness the synergy of sustainable development goals, and achieve circular economy. This study examined the performance feasibility of treating fluoride-contaminated surface and groundwater using raw and modified biochar synthesized from agricultural waste rice husk as problem-fixing renewable carbon-neutral material. Physicochemical characterizations of raw/modified biochars were investigated using FESEM-EDAX, FTIR, XRD, BET, CHSN, VSM, pH_pzc, Zeta potential, and particle size analysis were analyzed to identify the surface morphology, functional groups, structural, and electrokinetic behavior. In fluoride (F-) cycling, performance feasibility was tested at various governing factors, contact time (0-120 min), initial F- levels (10-50 mg L^-1), biochar dose (0.1-0.5 g L^-1), pH (2-9), salt strengths (0-50 mM), temperatures (301-328 K), and various co-occurring ions. Results revealed that activated magnetic biochar (AMB) possessed higher adsorption capacity than raw biochar (RB) and activated biochar (AB) at pH 7. The results indicated that maximum F- removal (98.13%) was achieved using AMB at pH 7 for 10 mg L^-1. Electrostatic attraction, ion exchange, pore fillings, and surface complexation govern F- removal mechanisms. Pseudo-second-order and Freundlich were the best fit kinetic and isotherm for F- sorption, respectively. Increased biochar dose drives an increase in active sites due to F- level gradient and mass transfer between biochar-fluoride interactions, which reported maximum mass transfer for AMB than RB and AB. Fluoride adsorption using AMB could be described through chemisorption processes at room temperature (301 K), though endothermic sorption follows the physisorption process. Fluoride removal efficiency reduced, from 67.70% to 53.23%, with increased salt concentrations from 0 to 50 mM NaCl solutions, respectively, due to increased hydrodynamic diameter. Biochar was used to treat natural fluoride-contaminated surface and groundwater in real-world problem-solving measures, showed removal efficiency of 91.20% and 95.61%, respectively, for 10 mg L^-1 F- contamination, and has been performed multiple times after systematic adsorption-desorption experiments. Lastly, techno-economic analysis was analyzed for biochar synthesis and F- treatment performance costs. Overall, our results revealed worth output and concluded with recommendations for future research on F- adsorption using biochar.

Evaluation of water fluoridation scheme in Cumbria: the CATFISH prospective longitudinal cohort study

Background

Water fluoridation was introduced in the UK against a background of high dental decay within the population. Levels of decay have dramatically reduced over the last 40 years following widespread use of fluoride toothpaste.

Objective

The aim of the CATFISH (Cumbrian Assessment of Teeth a Fluoride Intervention Study for Health) study was to address the question of whether or not the addition of fluoride to community drinking water, in a contemporary population, lead to a reduction in the number of children with caries and, if so, is this reduction cost-effective?

Design

A longitudinal prospective cohort design was used in two distinct recruited populations: (1) a birth cohort to assess systemic and topical effects of water fluoridation and (2) an older school cohort to assess the topical effects of drinking fluoridated water.

Setting

The study was conducted in Cumbria, UK. Broadly, the intervention group (i.e. individuals receiving fluoridated drinking water) were from the west of Cumbria and the control group were from the east of Cumbria.

Participants

Children who were lifetime residents of Cumbria were recruited. For the birth cohort, children were recruited at birth (2014–15), and followed until age 5 years. For the older school cohort, children were recruited at age 5 years (2013–14) and followed until the age of 11 years.

Intervention

The provision of a ‘reintroduced fluoridated water scheme’.

Main outcome measures

The primary outcome measure was the presence or absence of decay into dentine in the primary teeth (birth cohort) and permanent teeth (older school cohort). The cost per quality-adjusted life-year was also assessed.

Results

In the birth cohort (n = 1444), 17.4% of children in the intervention group had decay into dentine, compared with 21.4% of children in the control group. The evidence, after adjusting for deprivation, age and sex, with an adjusted odds ratio of 0.74 (95% confidence interval 0.56 to 0.98), suggested that water fluoridation was likely to have a modest beneficial effect. There was insufficient evidence of difference in the presence of decay in children in the older school cohort (n = 1192), with 19.1% of children in the intervention group having decay into dentine, compared with 21.9% of children in the control group (adjusted odds ratio 0.80, 95% confidence interval 0.58 to 1.09). The intervention was found to be likely to be cost-effective for both the birth cohort and the older school cohort at a willingness-to-pay threshold of £20,000 per quality-adjusted life-year. There was no significant difference in the performance of water fluoridation on caries experience across deprivation quintiles.

Conclusions

The prevalence of caries and the impact of water fluoridation was much smaller than previous studies have reported. The intervention was effective in the birth cohort group; however, the importance of the modest absolute reduction in caries (into dentine) needs to be considered against the use of other dental caries preventative measures. Longer-term follow-up will be required to fully understand the balance of benefits and potential risks (e.g. fluorosis) of water fluoridation in contemporary low-caries populations.

Limitations

The low response rates to the questionnaires reduced their value for generalisations. The observed numbers of children with decay and the postulated differences between the groups were far smaller than anticipated and, consequently, the power of the study was affected (i.e. increasing the uncertainty indicated in the confidence intervals).

Study registration

This study is registered as Integrated Research Application System 131824 and 149278.

Funding

This project was funded by the National Institute for Health and Care Research (NIHR) Public Health Research programme and will be published in full in Public Health Research; Vol. 10, No. 11. See the NIHR Journals Library website for further project information.

BDJ Open 2021 - our most successful year to date

This paper aims to provide an update on the previous version published towards the end of last year, titled 'BDJ Open (2019-2020) and the advantages of open access publishing'. In this paper, we will highlight articles published throughout 2021, in order to focus on which areas authors felt were important to publish open access and also which areas have been expanded upon in the journal. Furthermore, this paper will examine how open access publishing in BDJ Open has enabled the continuous process of hypothesis testing to be shared more widely, as well as how publishing protocols and early results open access gives strength to that by allowing earlier opportunity for comment by other researchers, both through the peer review process and through further correspondence to authors directly and to the journal editors who publish their work.

Provides an update on the previous 2019-2020 paper by examining articles published in BDJ Open in 2021, to highlight which areas researchers felt were important to publish open access.

Highlights the advantages of open access publishing to authors, readers and the scientific community, particularly in light of the ongoing COVID-19 pandemic.

Explores how open access publishing in BDJ Open has enabled the continuous process of hypothesis testing to be shared more widely, allowing earlier opportunity for comment by other researchers.

Fluoride in the drinking water and dental caries experience by tooth surface susceptibility among adults

Background

Dental caries is the most prevalent non-communicable health condition globally. The surface-based susceptibility hierarchy indicates that surfaces in the same group have similar susceptibility to caries, where the most susceptible group consists of occlusal surfaces of first molars and buccal surfaces of lower first molars, and the least susceptible surfaces are smooth and proximal surfaces of first premolars, canines and incisors. Therefore, fluoride in the drinking water could impact one group more than the other group. The present study examined the association between fluoride levels in the drinking water and dental caries experience in adults in the context of varying tooth surface susceptibility.

Methods

Data from the cross-sectional National Lithuanian Oral Health Survey conducted in 2017–2019 included a stratified random sample of 1398 35–74-year-olds (52% response rate). Dental caries experience in dentine was measured at a surface level. The surfaces were grouped according to their caries susceptibility (group 1 being the most and group 4 the least susceptible), and dental caries experience was calculated separately for each susceptibility group, creating four outcomes. Information about explanatory variable, fluoride levels in the drinking water, was provided by the water suppliers. The questionnaire inquired about potential determinants: sociodemographic characteristics and oral health-related behaviors. Chi-square, Mann–Whitney U and Kruskal Wallis tests were used for descriptive statistics, and linear regression analyses to examine the association between fluoride levels and four outcomes.

Results

The proportions of median decayed, missing, filled surfaces decreased following the surface-based susceptibility hierarchy (group 1–33%, group 2–28%, group 3–24%, group 4–15%). When adjusted for potential determinants, higher-level fluoride (≥ 0.7 ppm vs < 0.7 ppm) in the drinking water associated with lower dental caries experience in all surface-based susceptibility hierarchy groups; Group 1: β = − 0.23 (95 %CI − 0.44; − 0.001), Group 2: β = − 0.44 (95 %CI − 0.82; − 0.07), Group 3: β = − 1.14 (95 %CI − 1.88; − 0.41) and Group 4: β = − 6.28 (95 %CI − 9.29; − 3.30).

Conclusions

The higher-level fluoride in the drinking water associated with lower dental caries experience in adults and this was observed in all surface-based susceptibility groups. However, there is a need to validate the surface-based susceptibility hierarchy in longitudinal adult studies.